1. Field of the Invention
This invention lies in the field of magnetic tape drive units. More particularly, it concerns the design of a portable tester that may be used in the shop, or in the field, for testing magnetic tape drive units.
2. Description of the Prior Art
In the prior art, the majority of tape drive testers do not provide a method of directly evaluating peak shift, nor do they provide a method of evaluating peak shift or analog waveform under various data patterns. Normal shop procedure in adjusting a tape unit is to:
1. ADJUST THE TAPE DRIVE CIRCUITS OBSERVING ANALOG WAVE FORMS USING A TESTER THAT GENERATES A CONTINUOUS SQUARE WAVE SIGNAL EQUIVALENT TO THE OUTPUT OF A SIGNAL GENERATOR;
2. AFTER ADJUSTMENT IN THIS MANNER, THE TAPE DRIVE IS RUN ON ITS CONTROLLER IN THE RANDOM DATA MODE TO CHECK FOR ERRORS. If this step is judged acceptable;
3. THE CONTROLLER AND TAPE DRIVE ARE RUN ON THE CENTRAL PROCESSOR FOR FINAL ACCEPTANCE OF THE ERROR RATE ON THE TAPE DRIVE.
If either step 2 or step 3 is not acceptable, then step 1 must be repeated, or alternately, the controller is used as a tester while the drive is being adjusted.
This is a costly process because of the expensive equipment that is tied up, or at least partially tied up, during the adjustment process. This can be put in proper perspective when it is realized that each controller typically has four to 16 tape drives attached, all of which may be rendered inoperative, from the central processor's point of view, when step 2 is being performed.
This invention is directed to eliminating the trial and error approach, described above, in testing the tape drive units.